Selective conversion of butanol into liquid branched olefins over zeolites

The n -butanol to hydrocarbon (BTH) reaction can produce a series of valuable chemicals and clean fuel precursors. The BTH reaction over different zeolite catalysts (ZSM-5, ZSM-22, Meso-ZSM-22, and ZSM-35) with an emphasis on the production of liquid branched olefins which can be used as precursors for clean gasoline was investigated in this paper. It was found that the structure and acidity of zeolite significantly influences the product distribution in BTH reaction. ZSM-5 zeolite with medium micropore size and large intersections, which are not present in ZSM-22, led to aromatic-rich products and had a long lifetime. ZSM-22 and Meso-ZSM-22 zeolites with unidirectional 10-ring structure achieved a high selectivity to isobutylene and C5+ branched hydrocarbons. Moreover, the Meso-ZSM-22 obtained by desilication with a higher acidity density and improved diffusion property resulted in more liquid organic products than the parent ZSM-22. ZSM-35 exhibited a high product-shape-selectivity for producing isobutylene because of its unique irregular sheet structure and is not suitable for liquid olefin production.